Home Assistant prior 2023.8.0 data authenticity

Summaryinfo

A vulnerability was found in Home Assistant. It has been classified as critical. This affects an unknown part. Performing a manipulation results in data authenticity. This vulnerability was named CVE-2023-41896. The attack may be initiated remotely. There is no available exploit. Upgrading the affected component is recommended.

Detailsinfo

A vulnerability, which was classified as critical, was found in Home Assistant. This affects an unknown code block. The manipulation with an unknown input leads to a data authenticity vulnerability. CWE is classifying the issue as CWE-345. The product does not sufficiently verify the origin or authenticity of data, in a way that causes it to accept invalid data. This is going to have an impact on confidentiality, integrity, and availability. The summary by CVE is:

Home assistant is an open source home automation. Whilst auditing the frontend code to identify hidden parameters, Cure53 detected `auth_callback=1`, which is leveraged by the WebSocket authentication logic in tandem with the `state` parameter. The state parameter contains the `hassUrl`, which is subsequently utilized to establish a WebSocket connection. This behavior permits an attacker to create a malicious Home Assistant link with a modified state parameter that forces the frontend to connect to an alternative WebSocket backend. Henceforth, the attacker can spoof any WebSocket responses and trigger cross site scripting (XSS). Since the XSS is executed on the actual Home Assistant frontend domain, it can connect to the real Home Assistant backend, which essentially represents a comprehensive takeover scenario. Permitting the site to be iframed by other origins, as discussed in GHSA-935v-rmg9-44mw, renders this exploit substantially covert since a malicious website can obfuscate the compromise strategy in the background. However, even without this, the attacker can still send the `auth_callback` link directly to the victim user. To mitigate this issue, Cure53 advises modifying the WebSocket code’s authentication flow. An optimal implementation in this regard would not trust the `hassUrl` passed in by a GET parameter. Cure53 must stipulate the significant time required of the Cure53 consultants to identify an XSS vector, despite holding full control over the WebSocket responses. In many areas, data from the WebSocket was properly sanitized, which hinders post-exploitation. The audit team eventually detected the `js_url` for custom panels, though generally, the frontend exhibited reasonable security hardening. This issue has been addressed in Home Assistant Core version 2023.8.0 and in the npm package home-assistant-js-websocket in version 8.2.0. Users are advised to upgrade. There are no known workarounds for this vulnerability.

The weakness was presented 10/20/2023 as GHSA-935v-rmg9-44mw. It is possible to read the advisory at github.com. This vulnerability is uniquely identified as CVE-2023-41896 since 09/04/2023. It demands that the victim is doing some kind of user interaction. The technical details are unknown and an exploit is not publicly available.

Upgrading to version 2023.8.0 eliminates this vulnerability.

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• Home Assistant

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